Graduate School and Research Center in Digital Sciences

Multi-user searchable encryption in the cloud

Van Rompay, Cédric; Molva, Refik; Önen, Melek

Research Report RR-15-306

While Searchable Encryption (SE) has been widely studied, adapting it to the multi-user setting whereby many users can upload secret files or documents and delegate search operations to multiple other users still remains an interesting problem. In this paper we show that the adversarial models used in existing multi-user searchable encryption solutions are not realistic as they implicitly require that the cloud service provider cannot collude with some users. We then propose a stronger adversarial model, and propose a construction which is both practical and provably secure in this new model. The new solution combines the use of bilinear pairings with private information retrieval and introduces a new, non trusted entity called "proxy" to transform each user's search query into one instance per targeted file or document.

Document Bibtex

Title:Multi-user searchable encryption in the cloud
Department:Digital Security
Eurecom ref:4659
Copyright: © EURECOM. Personal use of this material is permitted. The definitive version of this paper was published in Research Report RR-15-306 and is available at :
Bibtex: @techreport{EURECOM+4659, year = {2015}, title = {{M}ulti-user searchable encryption in the cloud}, author = {{V}an {R}ompay, {C}{\'e}dric and {M}olva, {R}efik and {\"{O}}nen, {M}elek }, number = {EURECOM+4659}, month = {08}, institution = {Eurecom}, url = {},, }
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